JP7310404B2 - Liquid ejection head, head unit, device for ejecting liquid, and liquid ejection method - Google Patents

Description

The present invention relates to a liquid ejection head, a head unit, an apparatus for ejecting liquid, and a liquid ejection method.

2. Description of the Related Art As a liquid ejection head of a coating apparatus that performs coating or printing on a vehicle body or the like, for example, there is one that uses a valve-type nozzle disclosed in Patent Document 1. In this liquid ejection head, an electromagnetic drive mechanism is used as a drive means for opening and closing the valve, but in order to increase the drive speed (opening/closing speed) of the valve, there is also a piezoelectric drive mechanism.

Here, FIG. 10A is a cross-sectional view showing the conventional liquid ejection head when opened, and FIG. 10B is a cross-sectional view showing the conventional liquid ejection head when closed. The illustrated conventional liquid ejection head 100 includes a housing 101 having an ejection port 102 at its tip and an ink injection port 103 on its side wall, and a head reciprocating inside the housing 101 so as to face the ejection port 102 . A valve body 105 arranged movably and sealed with an O-ring 104 in a housing 101, and a piezoelectric actuator housed in the housing 101 while being connected to the valve body 105. 106 and a pair of leads 107 a and 107 b for power supply connected to the actuator 106 . The tip of the valve body 105 facing the ink ejection port 102 of the conventional liquid ejection head 100 is made of cemented carbide containing tungsten or the like to avoid wear.

As shown in FIG. 10A, when the valve body 105 is away from the ejection port 102, the ink chamber 108 is filled with ink injected from the ink inlet 103 around the tip of the valve body 105. As shown in FIG. there is When the actuator 106 is driven in this state, the actuator 106 expands and the ink facing the valve body 105 is pushed out to the ejection port 102 in the process of moving the valve body 105 toward the ejection port 102. As shown in 10(b), an ink dot is ejected from the ejection port 102. FIG.

Japanese Patent No. 4123897

However, the above-described conventional liquid ejection head has a problem in that it is difficult to use in applications where a sufficient distance is required between the liquid ejection head and the object to be coated, because the ejection speed of the ink dots is slow and the distance that the ink dots travel in a straight line is short. be.

Accordingly, the present invention has been made in view of such problems, and provides a liquid ejection head, a head unit, an apparatus for ejecting liquid, and a liquid ejection head capable of extending the linear distance of an ink dot more than a conventional liquid ejection head. , an object of the present invention is to provide a liquid ejection method.

In order to solve the above-mentioned problems, the invention according to claim 1 provides a liquid ejection head that controls the ejection of liquid by pressing a movably formed valve body toward an ejection port for ejecting liquid. The valve element has a recess opening toward the ejection port at a position facing the ejection port in the tip portion on the ejection port side , and the ejection port has a ejection surface with which the tip portion can come into contact. When the valve body is further pressed toward the discharge surface from a state in which the tip is in contact with the discharge surface, the tip is bent so that the volume of the recess is reduced. Formed to be deformable .

According to the liquid ejection head, the head unit, and the apparatus for ejecting liquid according to the present invention, there is an effect that the straight advance distance of the ink dots can be extended.

1 is a configuration diagram showing the configuration of an inkjet printer as an example of a device that ejects liquid according to an embodiment; FIG. Explanatory drawing showing an example of arrangement of the inkjet printer shown in FIG. Explanatory drawing showing another arrangement example of the inkjet printer shown in FIG. Explanatory drawing when an image is printed on a spherical surface with an inkjet printer FIG. 2 is a cross-sectional view of main parts of the liquid ejection head according to the embodiment; A cross-sectional view along AA in FIG. 5 and a cross-sectional view including the tip of the valve body It is a BB cross-sectional view in FIG. 5, and is a cross-sectional view including a sealing member. Enlarged cross-sectional view of the vicinity of the discharge port in FIG. FIG. 2 is an explanatory diagram showing the reaching distance of each ink dot of a liquid ejection head according to an embodiment and a conventional liquid ejection head; Cross-sectional view of a conventional liquid ejection head Sectional view of the head unit according to the embodiment Explanatory drawing of the liquid supply system Flowchart of liquid ejection operation

In the present application, a "device that ejects liquid" is a device that includes a liquid ejection head or a head unit having the liquid ejection head, drives the liquid ejection head, and ejects liquid. Devices that eject liquid include not only devices that can eject liquid onto an object to which liquid can adhere, but also devices that eject liquid into air or liquid.

The "liquid ejecting device" can include means for feeding, transporting, and ejecting an object to which liquid can adhere, as well as a pre-processing device, a post-processing device, and the like.

For example, as a "device that ejects liquid", an image forming device that ejects ink to form an image on paper, and powder is formed in layers to form a three-dimensional object (three-dimensional object). There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that ejects a modeling liquid onto a formed powder layer.

Further, the "apparatus for ejecting liquid" is not limited to one that visualizes significant images such as characters and figures with the ejected liquid. For example, it includes those that form patterns that have no meaning per se, and those that form three-dimensional images.

The above-mentioned "substance to which a liquid can adhere" means a substance to which a liquid can adhere at least temporarily, such as a substance to which a liquid adheres and adheres, a substance which adheres and permeates, and the like. Specific examples include media such as recording media such as paper, recording paper, recording paper, film, and cloth, electronic components such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and test cells. Yes, and unless otherwise specified, includes anything that has liquid on it.

The material of the above-mentioned "thing to which a liquid can adhere" may be paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc., as long as the liquid can adhere even temporarily.

Further, the "liquid" is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head, but it should have a viscosity of 30 mPa·s or less at room temperature and pressure, or by heating or cooling. Preferably. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional-imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium. , edible materials such as natural pigments, solutions, suspensions, emulsions, etc. These are, for example, inkjet inks, surface treatment liquids, components of electronic elements and light emitting elements, and formation of electronic circuit resist patterns It can be used for applications such as liquids for liquids and material liquids for three-dimensional modeling.

Further, the ``device for ejecting liquid'' includes a device in which a liquid ejection head and an object to which liquid can be adhered move relatively, but is not limited to this. Specific examples include a serial type apparatus having an element (liquid ejection head moving mechanism) that moves the liquid ejection head, and a line type apparatus that does not move the liquid ejection head.

In addition, as a "liquid ejecting device", there are other processing liquid coating devices that eject processing liquid onto the paper in order to apply the processing liquid to the surface of the paper for the purpose of modifying the surface of the paper, raw materials is dispersed in a solution, and is sprayed through a nozzle to granulate fine particles of the raw material.

In the present application, a "head unit" is a device having at least one liquid ejection head, a liquid supply channel that supplies liquid to the liquid ejection head, and a liquid supply port that supplies liquid to the liquid supply channel.

First, referring to FIGS. 1 to 4, the configuration of an inkjet printer 201 will be described as an example of a device for ejecting liquid to which the liquid ejection head according to the embodiment is applied. FIG. 1 is a configuration diagram showing the configuration of an inkjet printer 201 as an example of a device that ejects liquid according to an embodiment. FIG. 2 is an explanatory diagram showing an example of arrangement of the inkjet printer 201 shown in FIG. 1 with respect to the automobile M to be printed. FIG. 3 is an explanatory diagram showing another arrangement example of the inkjet printer 201 shown in FIG. 1 with respect to the automobile M to be printed. FIG. 4 is an explanatory diagram when an image is printed on a spherical surface by an inkjet printer. FIG. 4(a) is an explanatory diagram when an image is printed on a spherical surface by the inkjet printer 201, FIG. 4(b) is an explanatory diagram showing the result when a square is printed on a spherical surface, and FIG. FIG. 3 is an explanatory diagram of a case where quadrilaterals are continuously printed on a spherical surface by an inkjet printer 201;

As shown in FIG. 1, an inkjet printer 201 generally includes an inkjet print head 202, a camera 204 as a photographing means disposed near the print head 202, and the print head 202 and camera 204 in the X direction. The XY table 203 is operated based on the XY table 203 that moves in the Y direction, the image editing software S that edits the image taken by the camera 204, and a preset control program, and the ink is discharged from the print head 202. and a drive unit 211 that positions the camera 204 and the print head 202 at predetermined positions based on the control from the control unit 209 and performs photographing and printing operations. is configured with

The print head 202 is configured with a plurality of valve-type nozzles as liquid ejection heads that eject ink (liquid) toward the surface of the object M to be coated. It should be noted that the term “ink” here includes “paint”. Ink is ejected perpendicularly to the printhead 202 from each valve-shaped nozzle. That is, the ink ejection surface of the print head 202 is parallel to the XY plane formed by the movement of the XY table 203, and the ink dots ejected from each valve-shaped nozzle are perpendicular to the XY plane. direction. In addition, the ejection directions of the ink ejected from each valve type nozzle are parallel to each other. Each valve-type nozzle is connected to an ink tank of a predetermined color, and the ink tank is pressurized by a pressure device (not shown). If so, the ink dots can be ejected onto the print surface without any problem.

The XY table 203 generally includes an X-axis 205 formed with a linear movement mechanism and a Y-axis 206 that holds the X-axis 205 with two arms and moves the X-axis in the Y direction. A print head 202 and a camera 204, which will be described later, are attached to a slider (not shown) on the X axis. A shaft 207 is provided on the Y-axis 206, and by holding this shaft 207 with a robot arm 208, the print head 202 can be freely arranged at a predetermined position where printing is to be performed on the object M to be coated. It's like For example, when the object M to be coated is an automobile, it can be arranged horizontally as shown in FIG. 3 or arranged in the upper part as shown in FIG. The operation of the robot arm 208 is controlled based on a program stored in the control unit 209 in advance.

The camera 204 is arranged on a slider (not shown) on the X-axis 205 near the print head 202, and moves in the XY directions to scan a predetermined range of the print surface of the object M at fixed minute intervals while moving in the XY directions. take a picture. The camera 204 is a so-called digital camera, and as described above, the specification of the lens capable of capturing a plurality of subdivided images for a predetermined range of the surface to be printed and the specification such as resolution are appropriately selected. The camera 204 captures a plurality of subdivided images of the surface to be printed continuously and automatically according to a program provided in advance in the control unit 209 .

The control unit 209 includes a storage device for recording and saving various programs, data of captured images, data of images to be printed, etc., a central processing unit for executing various processes according to the programs, an input device such as a keyboard and a mouse, It is composed of a so-called microcomputer equipped with a DVD player or the like as necessary, and further equipped with a monitor 210 for displaying input information to the control unit 209, processing results by the control unit 209, and the like. The control unit 209 performs image processing on a plurality of subdivided image data captured by the camera 204 using image processing software, and produces a composite print surface obtained by projecting the print surface of the object to be coated M, which is not a plane, onto a plane. At the same time, the drawing target image A, which is an image to be printed so as to be continuous with the already printed image on the printed surface, is superimposed on the composite printing surface, and the drawing target is made continuous with the edge of the printed image. By editing the image A, an edited image B to be drawn is generated. For example, for the print image 302b (corresponding to the drawing target image A) shown in FIG. 4C, the print image 302b is aligned with the composite print surface so that the non-print area 303 is not formed between the adjacent print image 302a. Editing (deformation) is performed so as to generate an edited image B to be drawn. Then, by actually printing with the print head 202 based on the drawing target edit image B, it is possible to print the print image 302b without any gap from the already printed print image 302a. A driving unit 211 whose operation is controlled by a control unit 209 performs the photographing of a plurality of subdivided images by the camera 204 and the printing by ejecting ink from each nozzle of the print head 202 .

In FIG. 4A, when a two-dimensional square is printed on the surface (spherical surface) of a spherical object 301 to be coated by an inkjet nozzle, ink is ejected from each inkjet nozzle mounted on the nozzle head 300. The direction of ink ejection is shown. In FIG. 4(b), the ink ejected from each inkjet nozzle mounted on the nozzle head 300 is ejected in the direction perpendicular to the nozzle head 300, so the print image 302a printed on the surface of the object 301 to be coated is a square with a distorted periphery.

[Structure of Liquid Ejection Head]
The liquid ejection head 1 according to the embodiment will be described in detail below. FIG. 5 is a cross-sectional view of the main part of the embodiment of the liquid ejection head 1 according to the embodiment. 5(a) is a cross-sectional view showing the state immediately before the valve body 6 contacts the discharge port 2, FIG. 5(b) is a cross-sectional view showing the state where the valve body 6 contacts the discharge port 2, FIG. (c) is a cross-sectional view showing a state in which the tip portion 6A of the valve body 6 is compressed. FIG. 6 is a cross-sectional view taken along line AA in FIG. 7 is a cross-sectional view taken along the line BB in FIG. 5, and is a cross-sectional view including the sealing member 7. FIG.

As shown in FIG. 5, the liquid ejection head 1 is generally hollow and has an ejection port 2 for ejecting ink at its tip and an injection port 3 for injecting ink in the vicinity of the ejection port 2 . nozzle body 4; actuator (piezoelectric element) 5 incorporated in nozzle body 4 and expanding and contracting (expanding and contracting in the horizontal direction in FIGS. 5(a) to 5(c)) according to the application of voltage from the outside; a sealing member 7 fitted on the valve body 6 to prevent ink from flowing into the actuator 5; a pair of lead wires 8a for power supply connected to the actuator 5; 8b.

The nozzle body 4 is formed in a cylindrical shape or a square tube shape as a whole, and is closed except for the discharge port 2 and the injection port 3 . The ejection port 2 is a small opening formed at the tip of the nozzle body 4, through which ink dots are ejected. More specifically, one end of the nozzle body 4 in its extending direction is sealed by an end wall 4A (see FIG. 8), and the discharge port 2 is provided through the end wall 4A. In the following description, the inner surface of the end wall 4A is also referred to as the ejection surface 2B (see FIG. 8). The inlet 3 is provided on the side surface of the nozzle body 4 near the ejection port 2, is connected to an ink tank 23 (see FIG. 12), and is continuously injected with ink (or paint) by a pressurizing means 28 (see FIG. 12). ) is supplied to the ink chamber 9 . The liquid supply system 21 including the pressurizing means 28 will be described later with reference to FIG.

The actuator 5 is a piezoelectric element and is made of zirconia ceramics or the like. The shape and the like are appropriately set according to the amount of ejected ink dots and the like. The actuator 5 is operated by continuously applying a voltage having a predetermined waveform controlled by the control section 209 (see FIG. 1). The sealing member 7 is a packing, an O-ring, or the like, and is fitted on the valve body 6 to prevent ink from flowing from the inlet 3 side to the actuator 5 side. As shown in FIG. 7 , the sealing member 7 is provided to seal the gap between the inner peripheral surface of the nozzle body 4 and the outer peripheral surface of the valve body 6 .

As shown in FIG. 6, the valve body 6 has a shape (in this embodiment, a columnar shape) conforming to the inner shape of the nozzle body 4, and a part on the discharge port 2 side, that is, a tip portion 6A is made of an elastic resin (for example, Fluororesin, specifically "Teflon" (registered trademark of Dupont Co., Ltd.), and further, as shown in FIGS. is formed with a concave portion 6B that serves as an ink reservoir. The concave portion 6B has a size that covers the ejection port 2, that is, has an opening diameter larger than the diameter of the ejection port 2. As shown in FIG. Incidentally, the operation of the valve body 6 will be described later.

FIG. 8 is an enlarged cross-sectional view of the vicinity of the ejection port 2 in FIG. As shown in FIGS. 6 and 8, by making the opening diameter of the concave portion 6B larger than the nozzle diameter (the diameter of the ejection port 2), the ejection performance (speed, volume, straightness, etc.) can be further improved. Wear of the edge 2A can be eliminated. If the nozzle inner edge 2A is worn, there is a possibility that the needle (valve element 6) will not be able to successfully close the ejection port 2, resulting in ink leakage. Also, if the degree of scraping of both sides of the nozzle inner edge 2A (a pair of vertically opposed portions in FIG. 8) is asymmetrical, the flow of ink entering the ejection port 2 becomes uneven, leading to ejection bending. there is a possibility. In the present embodiment, wear of the nozzle inner edge 2A can be prevented, so that occurrence of these problems can be avoided.

A coating apparatus equipped with the liquid ejection heads 1 is configured by arranging in parallel a plurality of liquid ejection heads 1 that eject inks of different colors.

[Operation of Liquid Ejection Head 1]
Next, the operation of the liquid ejection head 1 described above will be described. When no voltage is applied to the actuator 5, the actuator 5 is in a normal state in which it is not deformed. As shown in FIG. is occurring. In this state, no pressure is applied to the ejection port 2, and since the diameter of the ejection port 2 is sufficiently small relative to the length of the ejection port 2, ink is not ejected from the ejection port 2. .

Next, when a predetermined voltage is applied to the actuator 5, deformation (elongation) occurs in its length direction (horizontal direction in FIG. 5). Since one end of the actuator 5 is fixed to the nozzle body 4, the side of the valve body 6 is extended and the valve body 6 is pressed, thereby ejecting ink dots and causing the valve body 6 to move as shown in FIG. 5(b). The end surface of the tip portion 6A of contacts the ejection surface 2B. At this time, ink is contained in the concave portion 6B of the tip portion 6A.

Since the tip portion 6A is made of elastic resin, as shown in FIG. 5(c), when the valve body 6 is further pressed, the tip portion 6A is further deformed as if being crushed. As a result, the valve body 6 presses the ink as the volume of the recessed portion 6B decreases, and the ink in the recessed portion 6B is pushed out. At this time, the deformation of the elastic resin, that is, the tip portion 6A is instantaneous (for example, 50 μs), so the ink in the concave portion 6B is ejected at a high speed (specifically, about 10 m/sec), and the flying distance of the ink dot, In particular, it is possible to lengthen the straight-ahead distance of ink dots. Incidentally, the ejection speed of a conventional valve-type inkjet nozzle is 5 to 6 m/sec as described above. In addition, since the ink in the concave portion 6B is ejected, the amount of ink ejected is greater than that of the conventional valve-type inkjet nozzle.

[Head unit configuration]
A configuration of a head unit 11 to which the liquid ejection head 1 described above is applied will be described with reference to FIG. FIG. 11 is a cross-sectional view of the head unit 11 according to the embodiment.

As shown in FIG. 11, the head unit 11 includes a plurality of (eight in the example of FIG. 11) liquid ejection heads 1, liquid supply paths 12 that supply ink (liquid) to the liquid ejection heads 1, and liquid supply paths. 12 and a liquid discharge port 14 for discharging ink from the liquid supply channel 12 .

The basic configuration of the plurality of liquid ejection heads 1 is the same as that described with reference to FIGS. 5 to 8, and the same reference numerals are used for corresponding elements in FIG.

In the head unit 11 of FIG. 11, eight liquid ejection heads 1 are provided such that the ejection ports 2 are arranged in one direction (horizontal direction in FIG. 11) at approximately equal intervals. Each of the liquid ejection heads 1 extends vertically so as to eject ink downward from ejection ports 2 at the bottom of the figure. Each liquid ejection head 1 in FIG. 11 is rotated approximately 90° counterclockwise around the ejection port 2 side from the state in FIG.

Liquid is supplied through the ink chamber 9 of each liquid ejection head 1 so that the ink flows from one side (left side in FIG. 11) to the other side (right side in FIG. 11) in the arrangement direction of the eight liquid ejection heads 1. A path 12 is provided. That is, each liquid ejection head 1 differs from the configuration in FIG. 5 in that the discharge port 15 is provided on the opposite side of the injection port 3 .

In the head unit 11 of FIG. 11, the liquid outlet 14 is normally closed by a valve or the like. The liquid discharge port 14 is configured to open the valve when cleaning the head unit 11 or the like, thereby facilitating cleaning of the inside of the head unit. Also, normally, ink is supplied from the liquid supply port 13, and the liquid supply path 12 is filled with the ink as shown in FIG.

[Configuration of liquid supply system]
Next, the liquid supply system 21 for the liquid ejection head 1 will be described with reference to FIG. FIG. 12 is an explanatory diagram of the liquid supply system 21. As shown in FIG.

Here, liquid tanks 23 (23A to 23C) are provided as airtight containers in which liquids 22 of respective colors to be discharged from the respective liquid discharge heads 1 (1A to 1C) are stored. The liquid tank 23 and the injection port 3 of the liquid ejection head 1 are connected via tubes 24, respectively.

On the other hand, the liquid tank 23 is connected to a compressor 27 via a pipe 26 including an air regulator 25 and supplied with pressurized air from the compressor 27 .

As a result, the pressurized liquid 22 of each color is supplied to the injection port 3 of each liquid ejection head 1, and the liquid 22 is ejected from the ejection port 2 according to the opening and closing of the valve body 6, as described above. The air regulator 25 , pipe 26 and compressor 27 function as pressurizing means 28 for continuously supplying liquid (ink) to the ink chamber 9 of the liquid ejection head 1 .

[Liquid ejection operation]
A liquid (ink) ejection method will be described with reference to FIG. FIG. 13 is a flow chart of the liquid ejection operation.

5 and the head unit 11 shown in FIG. 11, the ink chamber 9 is basically filled with ink. . Further, in the case of the head unit 11 of FIG. 11, the liquid outlet 14 is kept closed by an electromagnetic valve or the like.

From the above state, in step S1, the waveform (actually ON/OFF rectangular wave) is applied to the actuator 5 as described above, and the actuator 5 presses the valve body 6, thereby driving the valve body 6. , until the tip 6A of the valve body 6 contacts the discharge surface 2B. As a result, the valve body 6 presses the ink, and the ink is pressed toward the ejection port 2 and ejected from the ejection port 2 . At this time, the ink is stored in the concave portion 6B of the valve body 6 arranged at the position facing the ejection port 2. As shown in FIG.

In step S2, the actuator 5 is further driven to press the valve body 6 further toward the ejection port 2 from the position where it contacts the ejection surface 2B. At this time, the valve body 6 is pressed with a force that deforms the tip portion 6A of the valve body 6 so that the volume of the recessed portion 6B is reduced. As a result, the valve body 6 presses the ink inside the recess 6B, and the ink inside the recess 6B is ejected from the ejection port 2. As shown in FIG.

Thereafter, the valve body 6 is maintained in contact with the ejection surface 2B, thereby preventing ink from leaking from the ink chamber 9 to the ejection port 2, and the liquid ejection operation is completed.

When the present inventors measured the flying distance of ink dots in the embodiment shown in FIG. 5 and the conventional configuration shown in FIG. 10, the results shown in FIG. 9 were obtained. Various conditions in the measurement are as follows.

Gap g between the tip surface of the tip portion 6A and the inner surface of the nozzle body 4: 20 μm
Thickness t of tip 6A and inner diameter of recess 6B: 500 μm
Hole diameter of discharge port 2: 100 μm
Ink viscosity: 30mPa・S
Pressure applied to ink chamber 9: 0.45 MPa
Straight-ahead distance of an ink dot from the liquid ejection head 1 according to the present embodiment: d1
Linear distance of ink dot from conventional liquid ejection head 100: d2

FIG. 9 is an explanatory diagram showing how each ink reaches the liquid ejection head 1 according to the embodiment and the conventional liquid ejection head 100 . As shown in FIG. 9A, the distance that the ink dots 10 ejected from the liquid ejection head 1 according to the embodiment travel straight is 100 mm or more, whereas the conventional liquid ejection head shown in FIG. The distance that 100 ink dots 110 traveled straight was at most 50 to 60 mmm. As described above, it was confirmed that the liquid ejection head 1 according to the present embodiment can obtain an ink straight traveling distance of 1.67 to 2 times that of the conventional liquid ejection head 100 .

According to the liquid ejection head 1 according to the present embodiment, since the recess 6B is arranged at a position facing the ejection port 2 of the valve body 6, when the valve body 6 is pressed against the ejection port 2, the recess 6B is deformed so as to be crushed and the volume is reduced, the ink dots are pushed out at high speed, thereby increasing the straight traveling distance of the ink dots 10 . This makes it possible to increase the distance between the tip of the liquid ejection head 1 and the object 20 to be coated.

Further, the tip portion 6A of the valve body 6 arranged to face the discharge port 2 is made of elastic resin, and a concave portion 6B having an opening diameter larger than that of the discharge port 2 is provided on the tip surface of the tip portion 6A. Therefore, the amount of ink that can be accommodated in the recess 6B can be increased, and the reduction in the volume of the recess 6B when the valve body 6 is pressed can be accelerated, so the discharge amount can be increased. As a result, ejection performance (speed, volume, straightness, etc.) can be improved.

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from or changing the technical idea of the present invention.

REFERENCE SIGNS LIST 1 liquid ejection head 2 ejection port 3 inlet 4 nozzle main body 5 actuator 6 valve body 6A tip portion 6B concave portion 7 sealing member 8a lead wire 8b lead wire 9 ink chamber 10 ink dot 20 object to be coated 11 head unit

Claims (7)

A liquid ejection head that controls ejection of the liquid by pressing a movably formed valve body toward an ejection port that ejects the liquid,
the valve body has a recess opening toward the discharge port at a position facing the discharge port in a distal end portion on the discharge port side ;
The ejection port is formed on an ejection surface that can be contacted by the tip,
The tip portion of the valve body is deformable such that the volume of the recess is reduced by further pressing the valve body from a state in which the tip portion is in contact with the ejection surface and further pressed toward the ejection surface. Ru
liquid ejection head. 2. The liquid ejection head according to claim 1, wherein said recess has an opening larger than the diameter of said ejection port. 3. The liquid ejection head according to claim 1, wherein said tip portion of said valve body is made of elastic resin in which said concave portion is arranged . a liquid ejection head according to any one of claims 1 to 3;
a liquid supply path for supplying the liquid to the liquid ejection head;
a liquid supply port that supplies the liquid to the liquid supply path;
head unit with a liquid ejection head according to any one of claims 1 to 3;
a liquid ejection head moving mechanism for moving the liquid ejection head;
A device for ejecting a liquid having a head unit according to claim 4;
a liquid ejection head moving mechanism for moving the liquid ejection head included in the head unit;
A device for ejecting a liquid having A liquid ejection method for ejecting the liquid by pressing a movably formed valve body toward an ejection surface having an ejection port through which the liquid is ejected, comprising:
the valve body has a recess opening toward the discharge port at a position facing the discharge port in a distal end portion on the discharge port side;
pressing the valve body to bring the tip portion into contact with the discharge surface;
a step of further pressing the valve body toward the discharge surface to deform the tip portion so as to reduce the volume of the recess ;
A liquid ejection method comprising:

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